This invention relates to controlling glare from illumination devices that project illumination in a light path, such as headlights on automobiles, stadium lights, street lights, etc.
Many efforts have been made to reduce the discomfort caused by glare. In particular, blinding glare from on-coming or trailing automobile traffic and from street lighting poses a serious risk to automobile travel.
There are numerous other situations in which glare from lights causes discomfort or danger. For example, in a sports stadium lit for night use, glare from the lighting may interfere with good performance. Pilots may experience glare from airport landing lights or lights on other aircraft.
George U.S. Pat. No. 3,408,491 discloses an automobile headlight lens that includes cylindrical glass rods having an opaque wire positioned along the focal line of the rods to reduce glare to one side.
Cardone U.S. Pat. No. 3,402,981 discloses a glare-reduction screen for auto headlights having parallel, glare reducing horizontal veins spaced between a convex and a concave surface.
Meth U.S. Pat. No. 3,551,228 discloses a method of etching glass on a TV screen or picture glass to reduce reflected glare while minimizing loss of transparency. An HF-containing mixture is used to etch.
Tomforda U.S. Pat. No. 4,457,148 discloses a molded diffusion lens for an automobile headlight.
Bond U.S. Pat. No. 3,676,191 discloses an aerosol spray for applying a clear yellow dye to a headlight.